ii ALL EXISTENCES DIFFER 235 



ences in the density and rarity of the air, nor is the 

 horizon ever a perfect circle, owing to differences of 

 clearness in different directions. Object and faculty 

 alike are in continuous change ; all natural things are 

 continually altering their form or changing their 

 position ; therefore although they seem to sense to 

 remain fixed for a time, we know that this is impossible, 

 from the nature of things. 1 Whatsoever falls in the 

 scope of sense-perception, even the distant sphere 

 and stars, we judge to consist of the same elements, 

 therefore to be subject equally to perpetual variability 

 and vicissitude. Thus the atoms alone being simple, 

 and remaining ever the same no composite thing can be 

 the same for one moment even, as each is being altered 

 continually in all parts and on all sides by the efflux 

 and influx of innumerable atoms. 2 " Hence nothing is 

 perfectly straight, nothing perfectly circular among 

 composites, nothing absolutely solid but the atoms, 

 nothing absolutely void but the spaces between them." 

 The facet of a diamond appears to be a perfect plane, 

 perfectly compact, yet in reality it is rough and porous. 3 

 In matter no two lines or figures are, entirely equal, 

 nor can the same figure be repeated twice. 4 No man 

 is twice of the same weight, the very instruments by 

 which we measure and weigh things are themselves in 

 constant change, and the flux of atoms is never equal, 

 but now denser, now rarer. In general no two things 

 are of the same weight, length, sound, or number, nor 

 are two motions or parts of motion ever the same. 

 To say that ten trees are equal to ten others is to speak 

 merely from a logical point of view, for in fact each 

 is one in a peculiar and special sense. 5 " Equality is 



1 Op. Lat. i. 3. p. 199. 15. 2 P. 200. 20. 3 P. 200. 28, 201. 4 ; cf. 223. n. 

 4 De Mm. bk. ii. ch. 5. 5 P. 203. 27. 



